Iran's official news agency says the country's powerful Security Council has decided to lift the house arrest of the country's most senior dissident cleric. The ailing dissident was once in line to succeed the founder of Iran's Islamic Republic.

Iran's Supreme National Security Council has decided to lift the house arrest of Grand Ayatollah Hossein Ali Montazeri because of concerns about his deteriorating health.

The 80-year-old dissident cleric was placed under house arrest in 1997, after criticizing Iran's clerical hierarchy, including supreme leader Ayatollah Ali Khamenei. Ayatollah Montazeri was once in line to succeed the founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, but in 1988 their relationship soured when Mr. Montazeri criticized human rights abuses, the execution of political prisoners and the supreme leader himself, who died a year later.

Despite confinement to his house southwest of Tehran, the Islamic cleric has been a supporter of Iranian President Mohammad Khatami's efforts to reform the Islamic Republic. Mr. Montazeri has called for greater tolerance and limits on the power of the supreme leader.

Over the past several weeks Iranian politicians, clerics and academics have been calling for Mr. Montazeri's release, following reports his health has severely worsened. His son was quoted as saying his father has heart problems.

The Supreme National Security Council is Iran's highest decision-making body, made up of representatives of the supreme leader, as well as judicial, parliamentary and government leaders.

Iran's official news agency reported Monday that Mr. Montazeri's house arrest will be lifted Tuesday or Wednesday.